Build Resilient Planting Beds by Sheet Mulching
How-to guide by Leah Churner

• Define the area of your bed (~200 sq. ft is a good area).  If you want to plant in the fall, sheet mulch in the spring. If you want to plant in the spring, sheet mulch in the fall. 

• Cut the existing vegetation down  to the ground. Use a mower/string trimmer, or hand-pull weeds and lay them on top of the soil. If soil is  especially compacted, use a digging fork to loosen the soil a bit. 

• Spread your “fluffy” layer: partially decomposed leaves, crumbled mycelium blocks (optional: shredded paper, coffee grounds, algae from pond, grass clippings, spent grains from breweries).

• Water it in the fluffy layer to prevent it from blowing away.  

• Get your organic weed barrier ready. Remove plastic/staples from cardboard and lay it down, overlapping edges slightly. Other materials: newspaper, junk mail (remove any plastic), natural fibers (cotton or wool), even pet hair!

• Water this layer well to prevent the cardboard from becoming hydrophobic.

• Crumble more mycelium blocks on top of the cardboard. 

• Add 1-2” of compost: kitchen compost or store-bought. (I recommend an aged leaf mold compost,  rather than a manure-based compost,  to prevent adding excess Phosphorus to our native soil. Try the Heirloom Soils brand.)  

• Keep layering if you have enough other organic materials… if you’ve run out, go to the next step.   

• Add 2” or more of mulch: hardwood mulch, arborist wood chips, or shredded cedar. Mulch acts as a blanket to hide the cardboard and keep it in place. Water it in so that the sheet mulch is like a wrung-out sponge. 

• …Now, wait!. The sheet mulch will take 3-6 months for it to break down. Water weekly during summer drought.

• Use this downtime to make a planting plan.

• When the sheet mulch has decomposed enough that you can get through the cardboard with a shovel, it’s time to plant.

• If you get stuck, need advice on what to plant when and where, or have questions about how to solve other problems in your yard, book a garden coaching session with me!

Helpful links:

Horticulturati podcast: “The Multilayered Magic of Sheet Mulch”

Hothouse podcast: “Fungal Vision with Daniel Reyes”

Toby Henenway’s “Ultimate Bomb-Proof Sheet Mulch” recipe from Gaia’s Garden: A Guide to Home-Scale Permaculture  

Great blog post about sheet mulch from She Cooks, She Gardens

Guide to sheet mulching from Modern Farmer

Guide to sheet mulching from Lawn To Garden

Guide to sheet mulching from Permaculture.co.uk

Get free mushroom blocks from Central Texas Mycological Society

Fun facts about pill bugs. Don’t kill them! They’re beneficial insects crustaceans.

Fun facts about earthworms. They fertilize, aerate, and neutralize pH of soil!

Fresh arborist wood chips are the best mulch. Wood mulches in general do not reduce availability of nitrogen to plants. See this fact sheet from Washington State University.

Sourcing materials for your sheet mulch:

Arborist wood chips from Chip Drop: Website; video about why you might not want to use ChipDrop; video of why ChipDrop is great. Local vendors like Whittlesey and Geo Growers also sell bulk mulch by the yard.

Bagged leaf compost

Coffee grounds: Starbucks offers bagged coffee grounds for gardeners at participating locations. But check in with your local coffee shop! They DO HAVE FREE GROUNDS to give away. Ask a barista if you can drive around the back and pull grounds out of their compost bin. Bring a 5 gallon bucket because these grounds are messy.

Cardboard: Visit appliance retailers, grocery stores, and liquor stores for cardboard. Keep an eye out for plastic-coated, shiny cardboard (not ideal) and look for brown cardboard.

Spent brewery grains: Contact your local brewery and ask if you can have some spent grains! Again, bring a 5 gallon bucket to get them home.